Process of making sodium hydrosulfite.



omzrnn STATES .PATEN Tl OFFICE.

IOSEPH ROSENHEK AND HENRY MIROGOURT OF LYON, AND ROBERT LOUP, OF UALUIRE, FRANCE, ASSIGNORS T0 MANUFACTURE LYONNAISE DE MATIERES COLORANTES, O1 LYON, FRANCE.

PROCESS OF MAKING SODIUM HYDROSULFITE.

noo rrsx Nu Drawing.

Specification of Letters Yatent.

Application tiled April 2.1, 191.0. Serial No. 556,820. (Specimens) atentetl Apr. 25, 1911.

To u/t' wile/11 it may concern.

lie it known that we. Josnru l'losnxm-tn, doctor of philosophy. a subject of the Austro-lluug'arian .l'lmpire and a resident oi 21' Avenue de Xoaillcs. Lyon. in the Republic ot' l rance, llnxnr Mlnot'oturr, a subject ot the tepublic of France, and a resident ol 1?) Avenue lBerthclot, Lyon. France. and ltonmrr lilour, a Swi s subject, and residion at h (flu-min de Vassieux, tfaluire, I)e partment of the Rhone, France. have inrented some new and useful luiprovements in the Production of llydrosulfitc (tone pounds and Processes of Making the Same, ol which the 'lollowing is a specification.

it is known that the rather unstable sodium hydrosullitc ctmtainiirc 2 mol. of water of crystallizedion, which is obtained for instance by precipitating solutions of hydrosultite with connnon salt. may be transformed into a stable form by subsequently removing the water of crystallization by various method.

We have now discovered. a new process which allows of producing directly :1 precipitate of a stable hydrosulli te coi'upouud and which consists in the simultaneous act ion of jft'a'maldchyde-sodium sulloxylatc (hyraldite) and sodium bisulfite and common salt at a temperature exceeding 50 C. The hydrosulfite separates immediately in its anhydrousdorm. The new process is of special practical value by reason of the fact that the mother-liquor may be used again for the manufacture of hyraldite. The reaction is represented by the chemical equation 1 QNaIlSO +NaIISO CHHO:

' The process is illustrated by the follow- 1 in example: 4220 liters bisultitc sohu ion eontannin, 208 lnlos Nal-Ih cdntammg no tree sul'lurous acid, are heated to tit) (L. H0 45 i kilos (0111111011 salt are introduced,'and the temperature is raised to about 65 U. in a second vessel a concentrated solutionfof 11h kilos ()Il.(lll. .St .\'a, brought to about 230 liters by the addition of 'ater, are heated to (35 t. The contents ot' both ves sets are then mixed as rapidly as possible. The temperature increases by about 8" 0., and a heavy precipitate of anhydrous hydrosullitc separates. It is filtered oil', the mother-liquor removed carefully, and the precipitate dried with the necessary precaution o'l' preventii ig an oxidation by the oxygen of the air. The substance so obtained is a colorless or slightly pinkish colored powder easily solublcin water. It; consists ot small crystals of aeuminated prismatic shape. It is very voluminous, one liter weighing about- 800 grams. t An amount; of the salt containing one gram of sulfur reduces 4 gr. ot indigolt We clain1- 1 i,

The process of producingh stable hydrosulfite compound by mixing formaldehyde sodium sulfoxylate, sodium bisulfite and common salt in a concentrated solution at a temperature exceeding 50 C. substantially as described.

In witness whereof we have hereunto signed our names this sixth day of April 1910. in the presence of two subscribing witnesses.

JOSEPH ROSENHEK.

HENRY MIROCOURT. ROBERT LOUP.

Witnesses Tnonas N. BROWNE, MARIN VACIION. 

